Finding k for x is undefined at $x=2$

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Discussion Overview

The discussion revolves around the continuity of a piecewise function defined at a specific point, $x=2$. Participants explore the conditions under which the function can be continuous and the implications of discontinuities.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that for the function to be continuous at $x=2$, the limit as $x$ approaches 2 must equal the function value at that point, $f(2)$.
  • Another participant expresses uncertainty about the nature of discontinuities, questioning if a discontinuity always indicates a hole in the graph.
  • A later reply clarifies that not all discontinuities are holes, mentioning the existence of removable discontinuities, vertical asymptotes, and jumps as other types of discontinuities.

Areas of Agreement / Disagreement

Participants express differing views on the nature of discontinuities, with some focusing on the conditions for continuity while others discuss the implications of discontinuities without reaching a consensus.

Contextual Notes

There are unresolved assumptions regarding the definitions of continuity and types of discontinuities, as well as the specific calculations needed to determine the value of $k$.

karush
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If $f(x)=\begin{cases}
\dfrac{(2x+1)(x-2)}{x-2}, &\text{for } x\ne 2 \\[3pt] k, &\text{for } x=2 \\
\end{cases}$
for what number k will the function be continuous
a. 0 b. 1 c. 2 d. 3 e. 5
---------------------------------
I chose
[e] x is undefined at $x=2$ so
rewrite as $2x+1$
plug in $f(2)=2(2)+1=5=k$

hopefully
probably suggestions etc
 
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for f(x) to be continuous at x = 2 ...

$\displaystyle \lim_{x \to 2} f(x) = f(2)$
 
So discontinuous. Means a hole always?
 
karush said:
So discontinuous. Means a hole always?

not just a hole (a removable discontinuity)

also, a vertical asymptote or a jump (non-removable discontinuities)
 

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